Why is agitation necessary during pasteurization?

Agitation is necessary during pasteurization primarily to ensure that the product is uniformly heated. This uniform heating is critical because pasteurization relies on maintaining a specific temperature for a designated period to effectively kill harmful microorganisms and pathogens without significantly affecting the quality of the product. If the product were to heat unevenly, some portions might not reach the required temperature, compromising the safety and effectiveness of the pasteurization process. Agitation helps to maintain a consistent temperature throughout the product, preventing hot or cold spots and ensuring that all parts of the liquid are treated equally.